Plugging composition using swellable glass additives

ABSTRACT

Methods and compositions for plugging in a subterranean formation are provided. An example comprises providing a composition comprising a cementitious material, water, and a swellable glass additive, wherein the swellable glass additive comprises a plurality of interconnected organosilica nanoparticles; and introducing the composition into a subterranean formation.

BACKGROUND

Plugging compositions comprising swellable glass additives and methodsof use in subterranean formations are provided. The swellable glassadditives may comprise a plurality of interconnected organosilicananoparticles.

Temporary plugging may be a type of well operation. Generally, temporaryplugging may be a method for effecting well control or zonal isolation.Many different types of plugs may be used in temporary pluggingoperations, including retrievable plugs, degradable plugs, destroyableplugs, etc. Temporary plugs may comprise many different designs andmaterials. For example, mechanical plugs may include a framework with afrangible element. Destroyable plugs may be composed of soft metals oreven cement that may be destroyed through exposure to high pressurefluids and/or fracturing equipment; some may be drilled through toreestablish flow. Degradable plugs may lose their integrity upon contactwith another material, in what is typically a chemical reaction.

Problems with temporary plugs may generally be due to the time andexpense associated with removal of the plugs. Mechanical plugs may berun into the wellbore on tubing or cable and removed the same way. Whenthe mechanical plugs are to be removed, the tools must be removed fromthe wellbore first and then the plug may be removed. Removing the plugand associated tools from the wellbore may cause additional expense andrig downtime. Destroyable plugs, such as cement plugs, may be drilledthrough or fractured after use. However, drilling through or fracturingthe cement plug to reestablish flow within the wellbore often entailssignificant cost, rig downtime, and the use of additional equipment. Itis, therefore, desirable to develop a temporary plug which may bereadily removed to reestablish wellbore flow without incurring eithersignificant expense or rig downtime.

BRIEF DESCRIPTION OF THE DRAWINGS

These drawings illustrate certain aspects of some of the embodiments ofthe present invention, and should not be used to limit or define theinvention.

FIG. 1 is a schematic illustration of a system for the preparation anddelivery of a plugging composition comprising a cementitious materialand a swellable glass additive to a wellbore in accordance with certainembodiments.

FIG. 2 is a schematic illustration of surface equipment that may be usedin the placement of a plugging composition comprising a cementitiousmaterial and a swellable glass additive in a wellbore in accordance withcertain embodiments.

FIG. 3 is a schematic illustration of the placement of a pluggingcomposition comprising a cementitious material and a swellable glassadditive into a wellbore in accordance with certain embodiments.

FIG. 4 is a schematic illustration of the removal of a plug formed froma plugging composition comprising a cementitious material and aswellable glass additive in accordance with certain embodiments.

FIG. 5 is a photograph of a set plugging composition after contact withan organic solvent and in accordance with certain embodiments.

FIG. 6 is a photograph of a set plugging composition cut into threesections in accordance with certain embodiments.

FIG. 7 is a photograph of a set plugging composition in contact with anorganic solvent in accordance with certain embodiments.

FIG. 8 is a photograph of a set plugging composition in contact with anorganic solvent in accordance with certain embodiments.

DETAILED DESCRIPTION

Plugging compositions comprising swellable glass additives and methodsof use in subterranean formations are provided. The swellable glassadditives may comprise a plurality of interconnected organosilicananoparticles. The methods of using the plugging compositions comprisingthe swellable glass additives may comprise temporary plugging, temporaryabandonment, perforation plugging, and the like. The “swellable glassadditives” disclosed herein may be referred to as “swellable” becausethe additives swell when in contact with certain organics such asorganic solvents (e.g., crude oil, diesel, kerosene, and the like). Theamount of swelling that may be induced in the swellable glass additiveis a property determined by the specific swellable glass additive used,the specific organic solvent that contacts the swellable glass additive,the amount of organic solvent the contacts the swellable glass additive,and the duration of the contact the organic solvent makes with theswellable glass additive.

The swellable glass additives may be included in temporary pluggingcompositions. The swellable glass additives may be included in thetemporary plugging compositions in conjunction with a cementitiousmaterial. The swellable glass additive may be included in the temporaryplugging compositions for the purpose of swelling and subsequentlyfracturing the cementitious material after it has set. For example, atemporary plugging composition comprising a cementitious material and aswellable glass additive may be used in a temporary plugging operationto plug a section of a wellbore, for example, to isolate a zone of thewellbore. When it is desired to reestablish flow within the isolatedzone, the temporary plug may be removed by inducing swelling in theswellable glass additive. As the swellable glass additive swells, itapplies force to the hardened mass of the set cementitious material.This force may cause the hardened mass of the set cementitious materialto fracture into several smaller masses that are no longer capable ofplugging that zone of the wellbore and in so doing flow is reestablishedin that zone of the wellbore. An advantage of the compositions andmethods described herein is that it may not be necessary to drillthrough the set temporary plugs. An additional advantage is that the settemporary plugs need not be removed from the wellbore in order toreestablish flow. A further advantage is that the temporary plugs formedby the temporary plugging compositions need only be exposed to organicsolvents in order to fracture, and thus, the process of destroying thetemporary plug does not incur significant expense or rig downtimecompared to some of the other methods for removing and/or destroyingtemporary plugs.

The temporary plugging compositions may comprise one or morecementitious materials. Cementitious materials may comprise any of avariety of cementitious materials or cementitious combinations ofmaterials that are capable of setting or otherwise developingcompressive strength in the presence of water. Examples includehydraulic cement, kiln dust, and the like. The cementitious material maybe included in the temporary plugging compositions in an amount desiredfor a particular application. The cementitious material may be presentin an amount of about 50% to about 100% by weight of the temporaryplugging composition (e.g., about 50%, about 60%, about 70%, about 80%,about 90%, etc.). The cementitious material may be present in an amountof about 75% to about 99%, in an amount of about 80% to about 95%, or inan amount of about 85% to about 90% by weight of the temporary pluggingcomposition.

Any of a variety of hydraulic cements suitable for use in subterraneancementing operations may be used as the cementitious material of thetemporary plugging compositions. Suitable examples include hydrauliccements that comprise calcium, aluminum, silicon, oxygen and/or sulfur,which set and harden by reaction with water. Examples of such hydrauliccements, include, but are not limited to, Portland cements, pozzolanacements, gypsum cements, high-alumina-content cements, slag cements,silica cements, and combinations thereof. The hydraulic cement maycomprise a Portland cement. The Portland cements are classified asClasses A, C, H, or G cements according to American Petroleum Institute,API Specification for Materials and Testing for Well Cements, APISpecification 10, Fifth Ed., Jul. 1, 1990. In addition, the hydrauliccement may include cements classified as ASTM Type I, II, or III.

Kiln dust, as that term is used herein, refers to a solid materialgenerated as a by-product of the heating of certain materials in kilns.The term “kiln dust” as used herein is intended to include kiln dustmade as described herein and also equivalent forms of kiln dust. Kilndust typically exhibits cementitious properties in that it can set andharden in the presence of water. Examples of suitable kiln dusts includecement kiln dust, lime kiln dust, and combinations thereof. Cement kilndust may be generated as a by-product of cement production that isremoved from the gas stream and collected, for example, in a dustcollector. Usually, large quantities of cement kiln dust are collectedin the production of cement and are commonly disposed of as waste.Disposal of the cement kiln dust can add undesirable costs to themanufacture of the cement, as well as create environmental concernsassociated with its disposal. The chemical analysis of the cement kilndust from various cement manufactures varies depending on a number offactors, including the particular kiln feed, the efficiencies of thecement production operation, and the associated dust collection systems.Cement kin dust generally may comprise a variety of oxides, such asSiO₂, Al₂O₃, Fe₂O₃, CaO, MgO, SO₃, Na₂O, and K₂O. Problems may also beassociated with the disposal of lime kiln dust, which may be generatedas a by-product of the calcination of lime. The chemical analysis oflime kiln dust from various lime manufacturers varies depending on anumber of factors, including the particular limestone or dolomiticlimestone feed, the type of kiln, the mode of operation of the kiln, theefficiencies of the lime production operation, and the associated dustcollection systems. Lime kiln dust generally may comprise varyingamounts of free lime and free magnesium, lime stone, and/or dolomiticlimestone and a variety of oxides, such as SiO₂, Al₂O₃, Fe₂O₃, CaO, MgO,SO₃, Na₂O, and K₂O, and other components, such as chlorides.

Those of ordinary skill in the art will appreciate that the temporaryplugging compositions generally should have a density suitable for aparticular application. By way of example, the temporary pluggingcompositions may have a density of about 4 pounds per gallon (“lb/gal”)to about 20 lb/gal. The temporary plugging compositions may comprise ameans to reduce the density of the composition, such as hollowmicrospheres, low-density elastic beads, or other density-reducingadditives known in the art. Weighting agents may be used to increase thedensity of the temporary plugging composition. Those of ordinary skillin the art, with the benefit of this disclosure, will recognize theappropriate density for a particular application.

Swellable glass additives may be included in the temporary pluggingcompositions. The swellable glass additives may generally include aplurality of interconnected organosilica nanoparticles. The swellableglass additive may be included in a temporary plugging composition tofracture the hardened mass of set cementitious material. For example,the swellable glass additive, when exposed to a sufficient amount ofsuitable organic solvent may swell to a volume several times larger thanthe volume of the dried swellable glass additive. In addition, byinclusion of the swellable glass additive, a temporary plug may bedestroyed without the need to drill through it.

A wide variety of swellable glass additives may be employed. Generallythese additives may be described as a plurality of interconnectedorganosilica nanoparticles. More particularly, the swellable glassadditives may include bridged organosiloxane sol-gels comprising aplurality of alkysiloxy substituents. Without being limited by theory,these additives may generally be produced by a process that includestaking a bridged organosiloxane sol-gel comprising residual silanols andthen derivatizing the residual silanols of the sol-gel with a reagenthaving at least one group that is reactive with the residual silanolsand also at least one alkyl group. More specifically, preparation of thesol-gel may generally include forming the interconnected organosilcananoparticles from bridged silane precursor molecules throughpolymerization using an acid or base catalyst. After gelation, thesol-gel may be aged sufficiently to undergo syneresis. At this point,the sol-gel may be derivatized as described above to end-cap thesilanol-terminated polymers present on the sol-gel. Typicalderivatization reagents may include, but are not limited to,halosilanes, silazanes, disilazanes, and the like. The derivatizedsol-gel may then be dried, and/or ground into a fine powder, for use asa swellable glass additive. A commercially available example of aswellable glass additive is Osorb® swellable glass, available fromABSMaterials, Inc. of Wooster, Ohio.

The swellable glass additive is swellable upon contact with organicsolvents. The amount of swelling that may induced in the swellable glassadditive is a property determined by the specific swellable glassadditive used, the specific organic solvent that contacts the swellableglass additive, the amount of organic solvent the contacts the swellableglass additive, and the duration of the contact the organic solventmakes with the swellable glass additive. The swellable glass additivemay swell to a volume greater than about 1.5 times to about 10 times ormore the dried volume of the swellable glass additive. By way of examplethe swellable glass additive may swell to a volume of about 2 times,about 3 times, about 5 times, about 7 times, about 10 times, or more thedried volume of the swellable glass additive. As discussed above, theswellable glass additive may swell upon contact with organic solvents.By way of example and without limitation, the swellable glass additivemay swell upon contact with any of a variety of organic solvents such askerosene, diesel, crude oil, produced oil, ethanol, acetonitrile,methyl-t-butyl ethyl, dichloromethane, hydrocarbons such as hexane oroctane, aromatic hydrocarbons such as benzene, toluene, xylene,nitrobenzene, phenol, m-nitrophenol, chlorinated organic solvents suchas trichloroethylene, perchloroethylene, dichloroethylene, vinylchloride, polycarbonated biphenyls, and the like. Among other things,use of a swellable glass additive may help reduce the expense anddowntime associated with plug removal by providing a temporary plug thatis easily removed by contact with an organic solvent. This process ofplug removal may not require drilling through the plug or the use ofother plug destroying operations, equipment, or techniques.

Combinations of swellable glass additives may also be used. Otherswellable glass additives that behave in a similar fashion with respectto organic solvents may also be suitable. Those of ordinary skill in theart, with the benefit of this disclosure, will be able to select anappropriate swellable glass additive for use in the example temporaryplugging compositions based on a variety of factors, including theproperties required for the temporary plug and the desired swellingcharacteristics.

The swellable glass additives generally may be in particulate form foruse as a dry powder. As used herein, the term “particulate” refers tomaterials in solid state having a well-defined physical shape as well asthose with irregular geometries, including any particulates having thephysical shape of platelets, shavings, fibers, flakes, ribbons, rods,strips, spheroids, hollow beads, toroids, pellets, tablets, or any otherphysical shape. The swellable glass additives may be ground through anysufficient process to achieve a suitable size. The powdered form of theswellable glass additives may have a particle size in the range ofbetween about 1 micron to about 500 microns, about 10 microns to about350 microns, or about 50 microns to about 250 microns. However, particlesizes outside this disclosed range may also be suitable for particularapplications. The swellable glass additive also may be dried forinclusion into the temporary plugging composition and for ease oftransport. Without limitation, the swellable glass additive may be driedby any sufficient means to produce a swellable glass additive that iseasily added to the other components of the temporary pluggingcomposition. With the benefit of this disclosure, one having ordinaryskill in the art will be able to select an appropriately size ofswellable glass additive.

The swellable glass additive may be added to the temporary pluggingcomposition by any suitable procedure, including dry blending with thecementitious material before the addition of water, by mixing with thewater to be added to the cementitious material, or by mixing with thecementitious material consecutively with or after the addition of thewater. Moreover, the swellable glass additive may be included in thetemporary plugging compositions in an amount desired for a particularapplication. The swellable glass additive may be present in an amount ofabout 0.1% to about 15% by weight of the cementitious material (“bwoc”).The swellable glass additive may be present in an amount of about 1% toabout 10% bwoc, in an amount of about 0.1% to about 7.5% bwoc, or in anamount of about 1% to about 5% bwoc. The swellable glass additive may bepresent in an amount of about 5% bwoc or less. One of ordinary skill inthe art, with the benefit of this disclosure, will recognize theappropriate amount of swellable glass additive to use for a particularapplication.

Water is also included in the temporary plugging compositions. The watermay include, for example, freshwater, saltwater (e.g., water containingone or more salts dissolved therein), brine (e.g., saturated saltwaterproduced from a subterranean formations), seawater, or any combinationthereof. Generally, the water may be from any source, provided that thewater does not contain an excess of compounds that may undesirablyaffect other components in the temporary plugging compositions. Thewater may be included in an amount sufficient to form a pumpable fluid.The water may be included in the temporary plugging compositions in anamount in a range of from about 40% to about 200% bwoc. The water may beincluded in an amount in a range of from about 40% to about 150% bwoc.One of ordinary skill in the art, with the benefit of this disclosure,will recognize the appropriate amount of water to use for a particularapplication.

Set accelerators may be included in the temporary plugging compositionsto, for example, increase the rate of setting reactions. Control ofsetting time may allow for the ability to adjust to wellbore conditionsor customize set times for individual jobs. Examples of suitable setaccelerators may include, but are not limited to, aluminum sulfate,alums, calcium chloride, calcium sulfate, gypsum-hemihydrate, sodiumaluminate, sodium carbonate, sodium chloride, sodium silicate, sodiumsulfate, ferric chloride, or a combination thereof.

Set retarders may be included in the temporary plugging compositions to,for example, increase the thickening time of the temporary pluggingcompositions. Examples of suitable set retarders include, but are notlimited to, ammonium, alkali metals, alkaline earth metals, borax, metalsalts of calcium lignosulfonate, carboxymethyl hydroxyethyl cellulose,sulfoalkylated lignins, hydroxycarboxy acids, copolymers of2-acrylamido-2-methylpropane sulfonic acid salt and acrylic acid ormaleic acid, saturated salt, or a combination thereof. One example of asuitable sulfoalkylated lignin comprises a sulfomethylated lignin.

Weighting agents are typically materials that weigh more than water andmay be used to increase the density of a temporary plugging composition.By way of example, weighting agents may have a specific gravity of about2 or higher (e.g., about 2, about 4, etc.). Examples of weighting agentsthat may be used include, but are not limited to, hematite, hausmannite,and barite, and combinations thereof. Specific examples of suitableweighting agents include HI-DENSE® weighting agent, available fromHalliburton Energy Services, Inc.

Lightweight additives may be included the temporary pluggingcompositions to, for example, decrease the density of the temporaryplugging compositions. Examples of suitable lightweight additivesinclude, but are not limited to, bentonite, coal, diatomaceous earth,expanded perlite, fly ash, gilsonite, hollow microspheres, low-densityelastic beads, nitrogen, pozzolan-bentonite, sodium silicate,combinations thereof, or other lightweight additives known in the art.

Gas-generating additives may be included in the temporary pluggingcompositions to release gas at a predetermined time, which may bebeneficial to prevent gas migration from the formation through thetemporary plugging composition before it hardens. The generated gas maycombine with or inhibit the permeation of the temporary pluggingcomposition by formation gas. Examples of suitable gas-generatingadditives include, but are not limited to, metal particles (e.g.,aluminum powder) that react with an alkaline solution to generate a gas.

Mechanical-property-enhancing additives may be included in the temporaryplugging compositions to, for example, ensure adequate compressivestrength and long-term structural integrity. These properties can beaffected by the strains, stresses, temperature, pressure, and impacteffects from a subterranean environment. Examples of mechanical propertyenhancing additives include, but are not limited to, carbon fibers,glass fibers, metal fibers, mineral fibers, silica fibers, polymericelastomers, and latexes.

Dispersants may be included in the temporary plugging compositions.Where present, the dispersant should act, among other things, to controlthe rheology of the cement composition. While a variety of dispersantsknown to those skilled in the art may be used, examples of suitabledispersants include naphthalene sulfonic acid condensate withformaldehyde; acetone, formaldehyde, and sulfite condensate; melaminesulfonate condensed with formaldehyde; any combination thereof.

Defoaming additives may be included in the temporary pluggingcompositions to, for example, reduce tendency for the temporary pluggingcomposition to foam during mixing and pumping of the temporary pluggingcompositions. Examples of suitable defoaming additives include, but arenot limited to, polyol silicone compounds. Suitable defoaming additivesare available from Halliburton Energy Services, Inc., under the productname D-AIR™ defoamers.

Foaming additives (e.g., foaming surfactants) may be included to, forexample, facilitate foaming and/or stabilize the resultant foam formedtherewith. Examples of suitable foaming additives include, but are notlimited to: mixtures of an ammonium salt of an alkyl ether sulfate, acocoamidopropyl betaine surfactant, a cocoamidopropyl dimethylamineoxide surfactant, sodium chloride, and water; mixtures of an ammoniumsalt of an alkyl ether sulfate surfactant, a cocoamidopropylhydroxysultaine surfactant, a cocoamidopropyl dimethylamine oxidesurfactant, sodium chloride, and water; hydrolyzed keratin; mixtures ofan ethoxylated alcohol ether sulfate surfactant, an alkyl or alkeneamidopropyl betaine surfactant, and an alkyl or alkene dimethylamineoxide surfactant; aqueous solutions of an alpha-olefinic sulfonatesurfactant and a betaine surfactant; and combinations thereof. Anexample of a suitable foaming additive is ZONESEALANT™ 2000 agent,available from Halliburton Energy Services, Houston, Tex.

The temporary plugging compositions comprising a swellable glassadditive, cementitious material, and water may be used in a variety ofplugging applications. A method of the present invention may compriseproviding a temporary plugging composition comprising a swellable glassadditive, a cementitious material, and water; introducing the temporaryplugging composition into a subterranean formation; and allowing thetemporary plugging composition to set in the subterranean formation. Aswill be appreciated, the temporary plugging composition may be allowedto set in any suitable location in the subterranean formation where aplug may be desired. As used herein, introducing the cement compositioninto a subterranean formation includes introduction into any portion ofthe subterranean formation, including, without limitation, into awellbore drilled into the subterranean formation, into a near wellboreregion surrounding the wellbore, or into both. The plugging compositionmay be allowed to set into a hardened mass in the subterraneanformation. For example, the hardened mass may form a plug in a wellborein the subterranean formation and/or in one or more perforations in acasing and/or cement sheath in the wellbore.

A method for temporary plugging in a subterranean formation may compriseproviding a composition comprising a cementitious material, water, and aswellable glass additive, wherein the swellable glass additive comprisesa plurality of interconnected organosilica nanoparticles; andintroducing the composition into a subterranean formation. Thecementitious material in the composition may comprise kiln dust. Theplurality of interconnected organosilica in the swellable glass additivemay comprise a dried bridged organosiloxane sol-gel comprising aplurality of alkysiloxy substituents. The swellable glass additive maybe present in the composition in an amount of about 0.1% to about 15% byweight of the cementitious material. The composition may have a densityin a range of about 4 lb/gal to about 20 lb/gal. The composition mayfurther comprise a dispersant. The method may further comprise allowingthe composition to set in the subterranean formation to form a solidimpermeable mass. The solid impermeable mass may form a plug in a wellbore in the subterranean formation. The solid impermeable mass may forma plug in one or more perforations in a cement sheath and/or casing inthe subterranean formation. The method may further comprise contactingthe solid impermeable mass with an organic solvent. The organic solventmay be selected from the group consisting of kerosene, diesel, crudeoil, produced oil, ethanol, acetonitrile, methyl-t-butyl ethyl,dichloromethane, hexane, octane, benzene, toluene, xylene, naphthalene,nitrobenzene, phenol, m-nitrophenol, trichloroethylene,perchloroethylene, dichloroethylene, vinyl chloride, a polycarbonatedbiphenyl, and any combination thereof. The method may further compriseallowing the organic solvent to contact the solid impermeable mass for aperiod of about 24 hours or longer.

A temporary plugging composition may comprise a cementitious material; aswellable glass additive, wherein the swellable glass additive comprisesa plurality of interconnected organosilica nanoparticles; and water. Thecementitious material in the temporary plugging composition may comprisekiln dust. The plurality of interconnected organosilica nanoparticles inthe swellable glass additive may comprise a dried bridged organosiloxanesol-gel comprising a plurality of alkysiloxy substituents. The swellableglass additive be present in the temporary plugging composition in anamount of about 0.1% to about 10% by weight of the cementitiousmaterial. The temporary plugging composition may have a density of about4 lb/gal. to about 20 lb/gal. The temporary plugging composition mayfurther comprise an organic solvent. The organic solvent may be selectedfrom the group consisting of kerosene, diesel, crude oil, produced oil,ethanol, acetonitrile, methyl-t-butyl ethyl, dichloromethane, hexane,octane, benzene, toluene, xylene, naphthalene, nitrobenzene, phenol,m-nitrophenol, trichloroethylene, perchloroethylene, dichloroethylene,vinyl chloride, a polycarbonated biphenyl, and any combination thereof.

A plugging system may comprise a plugging composition comprising acementitious material, a swellable glass additive, and water; whereinthe swellable glass additive comprises a plurality of interconnectedorganosilica nanoparticles; an organic solvent; mixing equipment capableof mixing the cementitious material, swellable glass additive, andwater; and pumping equipment capable of pumping the plugging compositionand/or the organic solvent. The plurality of interconnected organosilicananoparticles in the swellable glass additive may comprise a driedbridged organosiloxane sol-gel comprising a plurality of alkysiloxysubstituents, and the organic solvent may kerosene. The plugging systemmay comprise kiln dust as the cementitious material. The plugging systemmay comprise the swellable glass additive be present in the pluggingcomposition in an amount of about 0.1% to about 15% by weight of thecementitious material. The plugging composition may have a density in arange of about 4 lb/gal to about 20 lb/gal. The plugging composition mayfurther comprise a dispersant. The organic solvent in the pluggingsystem may be selected from the group consisting of kerosene, diesel,crude oil, produced oil, ethanol, acetonitrile, methyl-t-butyl ethyl,dichloromethane, hexane, octane, benzene, toluene, xylene, naphthalene,nitrobenzene, phenol, m-nitrophenol, trichloroethylene,perchloroethylene, dichloroethylene, vinyl chloride, a polycarbonatedbiphenyl, and any combination thereof.

Example methods of using the temporary plugging composition will now bedescribed in more detail with reference to FIGS. 1-4. FIG. 1 illustratesa system 5 for preparation of a temporary plugging compositioncomprising a swellable glass additive, a cementitious material, andwater and the delivery of the temporary plugging composition to awellbore. As shown, the temporary plugging composition may be mixed inmixing equipment 10, such as a jet mixer, re-circulating mixer, or abatch mixer, for example, and then pumped via pumping equipment 15 tothe wellbore. The mixing equipment 10 and the pumping equipment 15 maybe disposed on one or more cement trucks as will be apparent to those ofordinary skill in the art. A jet mixer may be used, for example, tocontinuously mix a dry blend comprising the cementitious material andthe swellable glass additive, for example, with the water as it is beingpumped to the wellbore. Any of the embodiments of a temporary pluggingcomposition described herein may apply in the context of FIG. 1.

An example technique for placing a temporary plugging composition into asubterranean formation will now be described with reference to FIGS. 2and 3. FIG. 2 illustrates surface equipment 20 that may be used in theplacement of a temporary plugging composition. It should be noted thatwhile FIG. 2 generally depicts a land-based operation, those skilled inthe art will readily recognize that the principles described herein areequally applicable to subsea operations that employ floating orsea-based platforms and rigs, without departing from the scope of thedisclosure. As illustrated by FIG. 2, the surface equipment 20 mayinclude a cementing unit 25, which may include one or more cementtrucks. The cementing unit 25 may include mixing equipment 10 andpumping equipment 15 (as shown in FIG. 1) as will be apparent to thoseof ordinary skill in the art. The cementing unit 25 may pump a temporaryplugging composition 30, which may comprise a cementitious material, aswellable glass additive, and water, through a feed pipe 35 and to acementing head 40 which conveys the temporary plugging composition 30downhole. Any of the embodiments of a temporary plugging compositiondescribed herein may apply in the context of FIG. 2.

Turning now to FIG. 3, the temporary plugging composition 30 may beplaced into a subterranean formation 45. As illustrated, a wellbore 50may be drilled into one or more subterranean formations 45. While thewellbore 50 is shown extending generally vertically into the one or moresubterranean formation 45, the principles described herein are alsoapplicable to wellbores that extend at an angle through the one or moresubterranean formations 45, such as horizontal and slanted wellbores.Similarly, a cased wellbore is shown in FIG. 3, however, the wellbore 50need not be cased. Temporary plugging composition 30, once placed intowellbore 50 divides wellbore 50 into an upper portion 55 and a lowerportion 60 which are separated by the placed temporary pluggingcomposition. Both or either portions 55 and 60 may contain wellborefluids which may mix with a portion of temporary plugging composition30. The temporary plugging composition 30 is placed in wellbore 50 viacoiled tubing 65. It should be understood, however, that temporaryplugging composition 30 might be placed by other strings of tubularmembers such as a casing string or production tubing. The coiled tubing65 may be made up of a number of interconnected tubular components aboveand/or below the placed temporary plugging composition 30.

Placement of temporary plugging composition 30 via coiled tubing 65,generally entails inserting coiled tubing 65 to the desired depth andpumping temporary plugging composition 30 via pumping equipment 15 (asshown in FIG. 1) into the wellbore 50. Temporary plugging composition 30may be pumped down coiled tubing 65 until it exits at the desired zoneof wellbore 50 in which isolation is sought. Once placed, temporaryplugging composition 30 is allowed to set and harden into a solid mass,illustrated as plug 70 on FIG. 3. Once temporary plugging composition 30has set, upper portion 55 and lower portion 60 of wellbore 50 may beisolated from each other by plug 70 which blocks fluid flow between theupper portion 55 and lower portion 60. At this time, other operationsmay be conducted in wellbore 50 if desired. Any of the embodiments of atemporary plugging composition described herein may apply in the contextof FIG. 3.

FIG. 4 illustrates the removal of plug 70. When it is desired to removeplug 70, tubing, such as coiled tubing 65 or any other type ofsufficient tubing, may be inserted into wellbore 50 in a manner suchthat organic solvent 75 pumped from the coiled tubing 65 may contactplug 70. Organic solvent 75 may be any of the organic solvents describedherein. As organic solvent 75 contact a portion of plug 70. Theswellable glass additive within plug 70 that is exposed to organicsolvent 75 may begin to swell. As the swellable glass additive swells itexerts a force against the set cementitious particles of thecementitious material in plug 70. Thus, when the force exerted by theswelling of the swellable glass additive exceeds the bond strength ofthe set cementitious particles of the cementitious material in plug 70,plug 70 may begin to fracture. As plug 70 fractures, more of theswellable glass additive may be contacted by organic solvent 75 asorganic solvent 75 seeps into the newly formed fractures in plug 70.This seepage may induce further swelling of the swellable glass additiveand subsequently more fracturing of plug 70. This process may continueuntil plug 70 is comprised of several smaller pieces of set cementitiousparticles and no longer comprises one solid impermeable mass. As plug 70is fractured into smaller pieces, it is no longer capable of sealing andisolating upper portion 55 and lower portion 60 of wellbore 50 and thusflow between the upper portion 55 and lower portion 60 may bereestablished. The fractured pieces of plug 70 may be pumped out ofwellbore 50 if desired. The fracturing of plug 70 may not requireadditional fracturing steps or tools such as drilling through the plug,or fracturing the plug with fracturing equipment such as impact rods,bars, or high pressure fluids. Any of the embodiments of a temporaryplugging composition described herein may apply in the context of FIG.4.

The preceding description provides various embodiments of the temporaryplugging compositions containing different additives and concentrationsthereof, as well as methods of using the temporary pluggingcompositions. It should be understood that, although individualembodiments may be discussed herein, the present disclosure covers allcombinations of the disclosed embodiments, including, withoutlimitation, the different additive combinations, additiveconcentrations, and fluid properties.

The exemplary temporary plugging compositions disclosed herein maydirectly or indirectly affect one or more components or pieces ofequipment associated with the preparation, delivery, recapture,recycling, reuse, and/or disposal of the disclosed temporary pluggingcompositions. For example, the temporary plugging compositions maydirectly or indirectly affect one or more mixers, related mixingequipment, mud pits, storage facilities or units, compositionseparators, heat exchangers, sensors, gauges, pumps, compressors, andthe like used generate, store, monitor, regulate, and/or recondition theexemplary temporary plugging compositions and fluids containing thesame. The disclosed temporary plugging compositions may also directly orindirectly affect any transport or delivery equipment used to convey thetemporary plugging compositions to a well site or downhole such as, forexample, any transport vessels, conduits, pipelines, trucks, tubulars,and/or pipes used to compositionally move the temporary pluggingcompositions from one location to another, any pumps, compressors, ormotors (e.g., topside or downhole) used to drive the temporary pluggingcompositions, or fluids containing the same, into motion, any valves orrelated joints used to regulate the pressure or flow rate of thetemporary plugging compositions (or fluids containing the same), and anysensors (i.e., pressure and temperature), gauges, and/or combinationsthereof, and the like. The disclosed temporary plugging compositions mayalso directly or indirectly affect the various downhole equipment andtools that may come into contact with the temporary pluggingcompositions such as, but not limited to, wellbore casing, wellboreliner, completion string, insert strings, drill string, coiled tubing,slickline, wireline, drill pipe, drill collars, mud motors, downholemotors and/or pumps, cement pumps, surface-mounted motors and/or pumps,centralizers, turbolizers, scratchers, floats (e.g., shoes, collars,valves, etc.), logging tools and related telemetry equipment, actuators(e.g., electromechanical devices, hydromechanical devices, etc.),sliding sleeves, production sleeves, plugs, screens, filters, flowcontrol devices (e.g., inflow control devices, autonomous inflow controldevices, outflow control devices, etc.), couplings (e.g.,electro-hydraulic wet connect, dry connect, inductive coupler, etc.),control lines (e.g., electrical, fiber optic, hydraulic, etc.),surveillance lines, drill bits and reamers, sensors or distributedsensors, downhole heat exchangers, valves and corresponding actuationdevices, tool seals, packers, cement plugs, bridge plugs, and otherwellbore isolation devices, or components, and the like.

EXAMPLES

To facilitate a better understanding of the present embodiments, thefollowing examples of some of the preferred embodiments are given. In noway should such examples be read to limit, or to define, the scope ofthe disclosure.

Example 1

A temporary plugging composition comprising 1010 g of cement kiln dust,428 g of water, 10.10 g of dispersant, and 50.50 g of swellable glassadditive was mixed in a Waring® blender at 2000 rpm for 3 minutes. Thedispersant was CFR-3™ Cement Friction Reducer, available fromHalliburton Energy Services, Inc., of Houston, Tex. The swellable glassadditive was Osorb® swellable glass, available from ABSMaterials, Inc.of Wooster, Ohio. After blending, the destructive 24-hour compressivestrength of the sample was measured. The destructive compressivestrength was measured by allowing samples of the composition to cure in2″ by 4″ plastic cylinders that were cured in a water bath at 180° F.for 24 hours to form set cylinders. Immediately after removal from thewater bath, the destructive compressive strengths were determined usinga mechanical press in accordance with API RP 10B-2, Recommended Practicefor Testing Well Cements. The compressive strength averaged 686 psi. Thereported compressive strengths are an average for three (3) cylinders.Additionally, three sections of the cured sample were placed into abeaker of kerosene. It was visually observed that within 5 minutes, thesurface of the sections began to flake off. After 24 hours of submersionin kerosene, the sections had crumbled into several smaller pieces. Theaverage particle size distribution of the crumbled plug sections isdisplayed in Table 1 below.

TABLE 1 Particle Size Distribution D10 (μm) D50 (μm) D90 (μm) 88.6 5181670

The results indicate that exposure of a solid mass of a set temporaryplugging composition to an organic solvent such as kerosene, causes thesolid mass of set cementitious material to fracture and crumble intosmaller particles. FIG. 5 shows the resultant particles of the plugafter exposure to kerosene and dried.

Example 2

Two temporary plugging compositions were produced. The first (i.e.Sample 1) of the compositions comprised a combination cementitiousmaterial that was 300 g (i.e. 75%) Class H Portland cement and 100 g(i.e. 25%) cement kiln dust. Additionally 40 g (i.e. 10% bwoc) swellableglass additive and 182.4 g (i.e. 45.6% bwoc) water were added. Thesecond (i.e. Sample 2) of the compositions comprised a cementitiousmaterial that was 400 g (i.e. 100%) Class H Portland cement.Additionally 40 g (i.e. 10% bwoc) swellable glass additive and 165 g(i.e. 41.25% bwoc) water were added. Both Sample 1 and Sample 2 weremixed separately in a Waring® blender at 2000 rpm for 3 minutes. Theswellable glass additive was Osorb® swellable glass, available fromABSMaterials, Inc. of Wooster, Ohio. The samples were cured in 2″ by 4″plastic cylinders in a water bath at 180° F. for 24 hours to form setcylinders. Three sections of each cured Sample were placed into a beakerof kerosene. FIG. 6 shows an example of the three sections of Sample 2before contact with kerosene. After 24 hours of submersion in kerosene,the Samples were visually inspected.

The outermost surfaces of each section of Sample 1 had fractured intosmaller pieces and the overall sizes of each section were reduced. Thisreduction appears great enough to speculate that the section would notform an impermeable plug, however the larger size of the remainingsections may impede flow to some degree and therefore may requireadditional contact time with the organic solvent in order to furtherfracture the Sample. FIG. 7 illustrates the three sections of Sample 1after contact with Kerosene.

Sample 2 had two sections that had been fractured in a very similarmanner as the sections in Sample 1. However, one of the sections ofSample 2 saw very little fracturing. This may be due to insufficientmixing of the swellable glass additive with the composition so that theswellable glass additive was not evenly distributed throughout Sample 2.FIG. 8 illustrates the three sections of Sample 2 after contact withkerosene.

It should be understood that the compositions and methods are describedin terms of “comprising,” “containing,” or “including” variouscomponents or steps, the compositions and methods can also “consistessentially of” or “consist of” the various components and steps.Moreover, the indefinite articles “a” or “an,” as used in the claims,are defined herein to mean one or more than one of the element that itintroduces.

For the sake of brevity, only certain ranges are explicitly disclosedherein. However, ranges from any lower limit may be combined with anyupper limit to recite a range not explicitly recited, as well as, rangesfrom any lower limit may be combined with any other lower limit torecite a range not explicitly recited, in the same way, ranges from anyupper limit may be combined with any other upper limit to recite a rangenot explicitly recited. Additionally, whenever a numerical range with alower limit and an upper limit is disclosed, any number and any includedrange falling within the range are specifically disclosed. Inparticular, every range of values (of the form, “from about a to aboutb,” or, equivalently, “from approximately a to b,” or, equivalently,“from approximately a-b”) disclosed herein is to be understood to setforth every number and range encompassed within the broader range ofvalues even if not explicitly recited. Thus, every point or individualvalue may serve as its own lower or upper limit combined with any otherpoint or individual value or any other lower or upper limit, to recite arange not explicitly recited.

Therefore, the present embodiments are well adapted to attain the endsand advantages mentioned as well as those that are inherent therein. Theparticular embodiments disclosed above are illustrative only, as thepresent invention may be modified and practiced in different butequivalent manners apparent to those skilled in the art having thebenefit of the teachings herein. Although individual embodiments arediscussed, the invention covers all combinations of all thoseembodiments. Furthermore, no limitations are intended to the details ofconstruction or design herein shown, other than as described in theclaims below. Also, the terms in the claims have their plain, ordinarymeaning unless otherwise explicitly and clearly defined by the patentee.It is therefore evident that the particular illustrative embodimentsdisclosed above may be altered or modified and all such variations areconsidered within the scope and spirit of the present invention. Ifthere is any conflict in the usages of a word or term in thisspecification and one or more patent(s) or other documents that may beincorporated herein by reference, the definitions that are consistentwith this specification should be adopted.

What is claimed is:
 1. A method for temporary plugging in a subterraneanformation comprising: providing a composition comprising a cementitiousmaterial, water, and a swellable glass additive; introducing thecomposition into a subterranean formation; allowing the composition toset into a single solid mass; and allowing the swellable glass additiveto swell, such that the swelling of the swellable glass additivefractures the solid mass into two or more masses.
 2. The method of claim1 wherein the cementitious material comprises kiln dust.
 3. The methodof claim 1 wherein the swellable glass additive comprises a plurality ofinterconnected organosilica nanoparticles comprise a dried bridgedorganosiloxane sol-gel comprising a plurality of alkysiloxysubstituents.
 4. The method of claim 1 wherein the swellable glassadditive is present in the composition in an amount of about 0.1% toabout 15% by weight of the cementitious material.
 5. The method of claim1 wherein the composition has a density in a range of about 4 lb/gal toabout 20 lb/gal.
 6. The method of claim 1 wherein the compositionfurther comprises a dispersant.
 7. The method of claim 1 wherein thesolid mass is a solid impermeable mass.
 8. The method of claim 1 whereinthe solid mass forms a plug in a well bore in the subterraneanformation.
 9. The method of claim 1 wherein the solid mass forms a plugin one or more perforations in a cement sheath, casing, or combinationthereof in the subterranean formation.
 10. The method of claim 1,wherein the allowing the swellable glass additive to swell furthercomprises contacting the solid mass with an organic solvent.
 11. Themethod of claim 10 wherein the organic solvent comprises an organicsolvent selected from the group consisting of kerosene, diesel, crudeoil, produced oil, ethanol, acetonitrile, methyl-t-butyl ethyl,dichloromethane, hexane, octane, benzene, toluene, xylene, naphthalene,nitrobenzene, phenol, m-nitrophenol, trichloroethylene,perchloroethylene, dichloroethylene, vinyl chloride, a polycarbonatedbiphenyl, and any combination thereof.
 12. The method of 10 wherein theorganic solvent is allowed to contact the solid mass for a period ofabout 24 hours or longer.
 13. The method of claim 1 wherein theswellable glass additive comprises a plurality of interconnectedorganosilica nanoparticles.
 14. The method of claim 1 further comprisingmixing the cementitious material, the swellable glass additive, and thewater to form the composition; and pumping the composition into awellbore via pumping equipment.